1. Field of the Invention
This invention relates to a method of treating a surface, and more particularly a surface contaminated with radionuclides.
2. Discussion of the Prior Art
In the nuclear industry, surfaces of objects including mechanical components and constructional features may become contaminated with radionuclides such as cobalt-60, caesium-137 or strontium-90, or radioactive compounds such as PuO.sub.2 or UO.sub.2. Current practices for treating these surfaces include the use of chemical reagents, and abrasive jets. However, the contaminating radionuclides may penetrate deeply into the surface portion of the components or features and may present difficulties in being removed by these known surface treatments.
A number of alternative surface treatments have been tried by others. One such treatment is described in European patent specification number EP 91646 A1 which discloses a method of removing a radioactive metal oxide from the surface of a radioactive component by means of a laser beam directed at the surface. In UK patent specification number GB 2242060 A a concrete surface contaminated with tritium is treated by irradiating the surface with microwaves in order to vaporise water from the surface thereby removing tritium. German patent specification number DE 3500750 A discloses a method for removing radioactively contaminated surface layers of concrete from a reinforced concrete structure by inductively heating the reinforcing bars within the structure. In a further method, described in Japanese patent specification number JP 3002595 A, a radioactively contaminated concrete surface is removed by irradiating the surface with microwave radiation.
In all of these alternative treatments radioactive contamination is removed from a surface or else the contaminated surface is itself removed. Because of the nature of these treatments, the contamination becomes airborne thus necessitating downstream processing and leading to further complications and expense.